To determine the ripening characteristics of prune (Prunus domestica L.) fruits, we investigated, using eight different prune cultivars, whether there was (I) an increase of respiration and ethylene production on trees at the mature stage (except in 'Puchull'), (II) an increase after picking from trees at the mature stage, and (III) autocatalytic ethylene production or a respiration increase in mature fruit after exogenous ethylene treatment. The respiration and ethylene production of fruit on trees were estimated from the respiration and ethylene production values determined for picked harvested fruits, which were kept at 20℃ for 24 hours before measurement. All cultivars showed a gradual decrease of estimated respiration on trees from the early immature to late immature stages, reaching their lowest respiration levels. Then, six cultivars (excepting 'Edwards'), exhibited a climacteric rise at the mature stage. Seasonal changes in internal ethylene concentration and estimated ethylene production on trees showed almost the same tendency tendency. Ethylene production on trees was low at the immature stage in all cultivars, and exhibited a climacteric rise at the mature stage in six cultivars (not includingexcept 'Edwards'). 'Stanley' and 'Valor' showed increases of both respiration and ethylene production after exposure to 500 ppm exogenous ethylene for 48 hours. From these results, 'Puchull' and 'Edwards' were categorized as suppressed-climacteric types, while the other six cultivars, 'Purple Ais', 'Blue Tan', 'Stanley', 'Valor', 'President' and 'Marjorie's Seedling', were categorized as climacteric types.

　To elucidate the physico-chemical properties of the juice and the fruit as a whole for pomegranates harvested in the Yamanashi prefecture in Japan compared to that of the imported ones, following analysis were conducted. ① On average, the domestic fruit weight was approximately 150g per fruit, while the aril and juice ratios to the fruit weight were about 60% and 42%, respectively. The juice ratio to the aril weight was approximately 70%. These ratios were lower than those calculated for the imported fruit (approximately 400g per fruit), and not dependent on the fruit size. ② The brix measurement of pomegranate juice from domestic fruit was 17 and the sugar was glucose and fructose, while both ratios were nearly equivalent, it was slightly high in fructose. The same results were obtained for imported fruits. Titratable acidity in the imported fruit was much higher than that in the domestic fruit, which mainly composed of 0.7% oxalic acid. However the organic acid content in the imported fruit was 1.5% citric acid with a small amount of malic acid. ③ The dominant free-amino acids in the juices listed in order of high to low concentration were glutamine, glutamic acid, aspartic acid and serine. There were no significant differences between the juices from domestic And the imported fruit. Small quantities of sarcosine were detected in both juices. ④ Total polyphenol content in the juices was approximately 100mg% and 200mg% in the domestic and imported fruit, respectively. The HPLC analysis of the polyphenol revealed that punicalin and punicalagin were detected in the juices from the domestic fruit and not the imported fruit.

　Factors that deteriorate the quality of the fish paste products containing threadfin bream and the ability to suppress these effects were investigated. The myosin heavy chain (MHC) in the gel of threadfin bream surimi was degraded by heating from 40 to 60℃. The gel strength of threadfin bream was softer than that of Alaska pollack. The protease activity in threadfin bream surimi was 799 mU/g, which was approximately 6-fold higher the activity of Alaska pollack surimi. One trypsin-like serine type protease and two metalloproteases were detected using threadfin bream surimi. MHC degradation in the gel was suppressed by the addition of protease inhibitor. These results indicate that the decrease in the gel-forming ability in threadfin bream surimi was caused by internal protease that decomposed MHC. The addition of the trypsin inhibitor (TI) and soybean whey containing TI was effective for suppressing these effects.